从XML文件添加/删除元素

Question

I have an XML file with the following structure

<Users>
  <User>
    <ID>ABCD321</ID>
    <Name>Mike John</Name>
    <Modification>29/01/2014 16:05:34</Modification>
    <LDAP-Groups>
      <group Name="DOM_CLAS_48" />
    </LDAP-Groups>
  </User>
  <User>
    <ID>AXSD399</ID>
    <Name>Tamy Peters</Name>
    <Modification>29/01/2014 16:05:34</Modification>
    <LDAP-Groups>
      <group Name="DOM_SAP_208" />
      <group Name="DOM_SAP_201" />
      <group Name="DOM_SAP_263" />
    </LDAP-Groups>
  </User>
</Users>

I want to be able to Add/Remove a specific LDAP-GROUP example: remove <group Name="DOM_SAP_201" /> from the user who has ID <ID>AXSD399</ID> and add <group Name="DNS_SAP_999" /> to the user who has the ID <ID>ABCD321</ID>

what i tried so far:

public static void UpdateLDAP(string filename, string userId)
        {
            XDocument xdoc = XDocument.Load(filename);
            XElement user = (from xml2 in xdoc.Descendants("User")
                             let xElement = xml2.Element("LDAP-Groups")
                             where 
                             (from xml3 in xdoc.Descendants("User") 
                              let xUser = xml3.Element("ID")
                                  where xUser.Value == userId.ToUpper())
                              select xElement).FirstOrDefault();

            //........ 
        }

Answer 1

You maybe first get all groups for the given user then update your XML (to be honest i don't know how to update it)

public static List<string> GetGroupsForGivenUser(XDocument xdoc, string userId)
        {
            var users = (from user in xdoc.Descendants("User")
                         let xElement = user.Element("ID")
                         where xElement != null && xElement.Value == userId.ToUpper()
                         select new
                         {
                             Id = xElement.Value,
                             Ldap = user.Elements("LDAP-Groups")

                         }).ToList();

            return (
                    from user in users
                    from ldaps in user.Ldap
                    from ldap in ldaps.Elements("Group")
                    select ldap.Value
                ).ToList();
        }